Many devices have been proposed in the prior art which attach to golf clubs and are intended to improve a golfer's game by aiding his stroke, his stance, or the line of flight of the ball. Some of these devices require specially modified golf clubs; for example, U.S. Pat. No. 1,173,384 uses a collapsible indicator built into the club itself, while U.S. Pat. No. 3,292,928, U.S. Pat. No. 3,529,830, and U.S. Pat. No. 3,667,761 feature devices that screw or fit into apertures in the head of the club. Other devices have been constructed that fit onto any club and use mirrors as the sighting element; for example, U.S. Pat. No. 2,898,109 uses a mirror which clamps to the shaft of the club. While these devices have the advantage of being usable with any club, they tend to be cumbersome to use, costly to manufacture, or wholly ineffective.
Finally, a number of devices have been proposed which use sighting elements that can be removably affixed to either the head or the shaft of a golf club. For example, U.S. Pat. No. 4,174,838 utilizes an apparatus containing a clamping device and pendulum means for aligning the sighting element with the ball; U.S. Pat. No. 3,198,525 features a foldable sighting element which attaches to the shaft of a club; and U.S. Pat. No. 4,720,110 features a metal shank with a threaded sighting element on one end and a magnet on the other end. While these devices can be removably fitted onto any club, their sighting elements are horizontally disposed in a direction normal to the plane of the hitting face of a golf club. This arrangement is cumbersome in use because it causes the sighting element to come into contact with the ground or the ball on the forward or backward swing. When the vertical distance between the sighting element and the head of the club is increased to avoid these problems, the sighting element is less effective. U.S. Pat. No. 4,720,110 has attempted to deal with some of these problems by having the sighting element in some of its embodiments extend to the rear of the hitting face of the club. However, this arrangement is less effective in providing direction than an arrangement where the sighting element extends over both faces of the club. In addition, U.S. Pat. No. 4,720,110 calls for use of the device in conjunction with markings on the club itself.